An electrochromic device is conventionally understood as being a system that includes a material whose optical characteristics (e.g. the colour) vary when subjected to a potential difference. Throughout the electrochemical process (electrochromic activation by means of the potential difference, wherein the material suffers an oxidation or reduction process—electron loss or gain, respectively) there is a charge flow which is necessary to balance by means of an electrolyte—a mixture of chemical substances (ions—negatively and positively charged particles) that have the ability to “move” between the electrodes. Finally, and in order to complete the circuit, an electric charge balance substance is required. The function of this latter element is to follow the electrochemical process of the electrochromic component as far as electrons are concerned. [1-4]
Electrochromic devices are usually used in glass or plastic substrates that are applied to windows, namely in the building and automotive industries, but the substrate functionalization and the integration thereof in active devices constitute an innovation.
Beyond that, we are unaware of the existence of any electrochromic transistor devices like the ones proposed herein.
In the following we will describe the state of the art and patents preceding this invention, with which it might be related.
Concerning the research and development or application fields, we are unaware of any activity in close proximity or corresponding to an aspect of the presently disclosed subject matter, as far as the integrated process and product features and resulting uses are concerned.
By searching the literature we found the following patents related to classic electrochromic devices, of which we present some examples:
US 2008/0297878 A1 refers to an electrochromic device including a fibrous organic substrate that bears nothing in common with the now proposed electrochromic transistor device.
PCT/PT2009/000008 refers to the processing of electric and or electronic and or electrochromic elements in cellulosic material substrates, distinct from aspects of the different invention.
The Portuguese patent application no 103951 of 2008 refers to the use of cellulosic or bioorganic-based paper as physical support for the processing of electronic devices and systems, and not to the integration thereof in the manufacture process and maintenance of the electronic devices and systems. It bears nothing in common with the presently disclosed subject matter.
The Portuguese patent application 103671 refers to the use of electrochromic device structures as solid state timers, bearing nothing in common with the presently disclosed subject matter.
The Portuguese patent applications 103998 and 103999 refer to transistors wherein the paper is an active part of the devices. In this case, however, neither the paper is functionalized nor the devices change their colour or are controlled by the ionic and electronic currents. That is to say, an aspect of the invention is distinct from the presently disclosed subject matter.
From what was just presented one can conclude that, to our knowledge, there is no patent application or published result concerning the creation of product and processes mentioned in the presently disclosed subject matter.
The cited patents and references correspond to the state of the art to which the presently disclosed subject matter pertains and with which it has some overlapping borderline features, related to the used processes and materials and the fact that the manufacture processes and techniques are similar in some cases. We are, however, unaware of the existence of any works and patents or technical patent applications that focus on aspects of the presently disclosed subject matter: electrochromic transistor using functionalized or non-functionalized substrates.
The presently disclosed subject matter can consist of or include creating a new active device that acts simultaneously as switching key and electrochromic device, using non-functionalized or functionalized substrates, that is to say, wherein the substrate itself contains in its bulk the electrolyte and the electrochromic materials, such as, for example, polymer or natural, synthetic, or mixed cellulosic paper. We are unaware of the implementation of this kind of devices, whether in an attempted or fully accomplished laboratory form. These are aspects of the presently disclosed subject matter that results in a hybrid, and yet monolithic quality—concerning the integration of electronic components that produce new effects and add a new value when applying the invention—that is not present in the systems belonging to the state of the art.